Process of manufacaturing noninflammable articles of organic fibrous materials



Patented Aug. 30,1938

PATENT OFFICE PROCESS OF MANUFACTUBIN G NONIN- LE ARTICLES OF ORGANIC Fl- FLALIMAB BROUS MATERIALS Bernhard Miiller, Berlin-Charlottenburg, Germany, assignor to Kutgerswerke-Aktiengesellschait, Berlin, Germany No Drawing. Application October 26, 1936, Se-

rial No. 107,646. In Germany December 14,

'1 Claims. (01. 92-21) My present inventionrelates to a process of making non-inflammable plates, slabs, or other articles from fibrous materials, for instance from fibers of wood, straw or the like. According to my invention the fibrous materials from which plates, slabs or other articles are produced in a known manner, are soaked in an aqueous solution containing as essential components ammonia, water.- soluble phosphates such as ammonium phosphate and water-soluble silicofluorides, especially magnesium silicofiuoride. From such solutions diflicultly soluble phosphates and silicic acid are. precipitated on the fibers which are worked up to plates, slabs or the like in the usual way.

Example-470 kilos of a mass consisting of a mixture of wood pulp and straw pulp are beaten in a hollander of a capacity of about 4 ohm. To the aqueous pulp 85 kilos of aqueous ammonia of 25% and 24 kilos of monoammonium phosphate 0 (NH.H2PO4) dissolved in 110 kilos of water are added and uniformly distributed. Finally- 57 kilos of magnesium silicofiuoride (MgSiFs.6HzO) dissolved in 150 kilos of water are added in small portions, each portion being uniformly distributed :5 in the aqueous mass. The pulp is beaten in the hollander for about 30 minutes and is then worked up in the usual manner to plates, slabs or the like.

The ammonium phosphate reacts in the presl0 ence of ammonia with magnesium silicofiuoride according to the following equation:

fluence of strong heat, but they are non-inflammable and do not burn with a flame. This high resistivity against heat can only be attained if in accordance with my invention the fibers contain silicic acid beside a water insoluble metal ammonium phosphate.

What I claim is:

1. In a process of manufacturing non-inflammable articles of organic fibrous materials the steps of preparing an aqueous pulp of an organic fibrous material, adding to said pulp a solution containing as essential components ammonium hydroxide and a water soluble salt of phosphoric acid, selected from the group consisting of the phosphates of ammonium, sodium or potassium, admixing to the mixture thus obtained an aqueous solution of a water soluble metal salt of fluosilicic acid selected from the group consisting of the fiuosilicates of magnesium, zinc and aluminum to precipitate a water insoluble metal ammonium phosphate and silicic acid on the fibres of said fibrous material, and then forming the treated pulp into non-inflammable articles.

2. A process according to claim 1, in which monoammonium phosphate is used as the water soluble salt of phosphoric acid and magnesium silicofiuoride is used as the water soluble metal salt of fluosilicic acid.

3. A process according to claim 1, in which 1 mol. of monoammonium phosphate, 1 mol. of magnesium silicofiuoride and 6 mols oi ammonium hydroxide are used.

4. A process according to claim 1, in which monoammonium phosphate is used as the water soluble salt of phosphoric acid and zinc silicofluoride is used as the water soluble metal salt of fluosilicic acid. 5. A process according to claim 1, in which sodium phosphate is used as the water soluble salt of phosphoric acid.

6. A process according to claim 1, in which potassium phosphate is used as the water soluble salt of phosphoric acid.

'l. A process according to claim 1, in which aluminum silicofiuoride is used as the water soluble salt of fluosilicic acid.

. BERNHARD Mum-ER. 

